#chat {
  overflow: hidden;
  border-radius: 3px;

  .sidebar, .main {
    height: 100%;
  }
  .sidebar {
    float: left;
    width: 200px;
    color: #f4f4f4;
    background-color: #2e3238;
  }
  .main {
    position: relative;
    overflow: hidden;
    background-color: #eee;
  }
  .m-text {
    position: absolute;
    width: 100%;
    bottom: 0;
    left: 0;
  }
  .m-message {
    height: ~'calc(100% - 160px)';
  }
}